Technical Abstract:
Red clover and alfalfa are legume forages with many nutritional benefits as ruminant feeds. Although red clover lacks many agronomic traits of alfalfa, silage produced from red clover has higher total protein available to the animal. Degradation of alfalfa protein during ensiling results in losses of up to $70 per ha. Native proteases degrade 44 to 87% of alfalfa protein into ammonia, amino acids and small peptides. Red clover, a forage of similar protein content as alfalfa, has up to 90% less proteolysis than alfalfa during ensiling. This observation suggests that red clover would be an ideal legume for ensiling if problems of lower yield, low field stand persistency, and slow drying rate in the field could be overcome. Perhaps there are ways to take the best qualities of red clover and combine them with alfalfa. Reduced proteolysis in red clover is not due to differences in the inherent proteolytic activity or protein composition compared to alfalfa. The improved true protein content of red clover silage appears to be due to the presence of a soluble polyphenol oxidase (PPO) and soluble polyphenols (SPP) that inactivate hydrolytic enzymes upon exposure of cellular contents to oxygen. Alfalfa lacks a soluble PPO and SPP and tends to maintain a high level of proteolytic activity during ensiling resulting in substantial protein losses (50 to 80%). Perhaps clues can be obtained from red clover to develop a silage treatment that would decrease protein losses in silages from other forages.